You might get a video game, or you might get a stuffed purple unicorn. You might get an iPad, or you might wind up empty-handed.

No matter the outcome, Reddit's anonymous gift exchanges are quickly becoming a holiday tradition. This year, the online community is going for a Guinness World Record, in the newly created category of Largest Online Secret Santa Game.

"This has become a lot of people's one Christmas gift," said Dan McComas, founder of RedditGifts, which organizes the exchanges.

McComas started Reddit Secret Santa in 2009 for fun as a side project in AskReddit, one of the social news site's most popular sections. Now, he and his wife, Jessica, are full-time employees of Reddit Inc., which is based in San Francisco. And what began with more than 4,000 participants that Christmas has ballooned this year to nearly 40,000, from 114 countries.

The anonymity baked into Reddit's design means that many Santas "stalk" their matches online to drum up gift ideas. Last year, one user, or Redditor, painted his giftee an old-fashioned portrait using the publicly visible photos he found on his match's Facebook profile.

'Kindhearted' stalking

McComas called Redditors' detective work a "kindhearted kind of stalking."

"I've got a pretty good idea of what is on the Internet about me," McComas said. "I would think that most people, when they sign up, think about what somebody's going to be able to find."

Being paired with a stranger who might live down the street or across the globe means not everyone is guaranteed to get a gift. But the program bans Santas who get but don't give, and encourages all to be generous and thoughtful.

Redditors have spent nearly $1.3 million on gifts and shipping for Secret Santa 2011, Reddit's 10th gift exchange in the past two years.

"It's just kind of a really fun idea," said San Jose State graduate student May Nguyen, who joined Reddit more than four years ago. "It's fun to find out more about your giftee and to put some thought into making another person's day better."

"Let's put a box together and make it really cool and make it happy," said Mountain View Redditor Michelle Diederich. "When that person opens it, whoever they are, they're going to get that energy of just being loved for that moment."

Some of the more generous gifts have included Kindles, iPads, electric guitars, digital cameras and $1,500 in cash. Early in this year's exchange, a 24-year-old participant from Atlanta who had been on Reddit fewer than two months received tickets for a four-day vacation to the Bahamas on Norwegian Cruise Line.

Visiting RedditGifts. com to find out your giftee's basic information on match day (held this year on Black Friday) is something of an event itself.

"I spent my Thanksgiving at a punk bar," Redditor Meagan Tarantelli said in a video recorded on match day. "I stayed out till 7 in the morning, and the first thing I wanted to do when I woke up was find out who I got for Reddit."

Even the site administrators can't avoid being stalked by their Santas.

Reddit Gifts is quickly becoming a holiday tradition

Media: San Francisco Chronicle

"My Secret Santa ... detected that I had a dog and that I theorized that my dog would be good in the event of a zombie apocalypse," said Reddit General Manager Erik Martin. "So they got me a dog tag, with my address personalized, that says, 'I fight zombies' on it, and my dog wears that to this day."

Martin said the Secret Santa exchanges put the Internet's best face on display.

"Often in the media, the Internet culture gets portrayed as kids in their basement, and geeks and hackers and people who are socially disinterested and rude," Martin said. "But that's totally not the case, and this is a great showcase of that."

Of course, there have been Redditors disappointed by the results of the gift exchanges. In the four biggest completed swaps so far - two for Christmas and two for a made-up Reddit holiday called Arbitrary Day - nearly 16 percent of Redditors matched with a giftee were left without a gift.

No gift rematch

As of Friday, about 8 percent of this year's participants had not yet shipped a present, according to statistics posted on RedditGifts.com. However, the site tries to rematch everyone who doesn't get something with a trusted volunteer Santa in an optional second round of giving.

Even when gifts arrive as planned, McComas said drama and debate about their appropriateness or quality wind up in his in-box.

"People are just emotional around the holidays," he said.

Perhaps the most infamous story is the "paper clips incident" from the first Secret Santa, in 2009. Kyle Brady, then a computer science student at San Jose State, sent his giftee a Photoshopped picture of a bobcat and four red-and-green paper clips from his desk as a joke.

Brady said he intended to send a real gift afterward, but changed his mind when the recipient complained on Reddit.

"He could've come and found me, but he took it public immediately and whined about it in a very self-pitying sort of way," Brady said.

The site has been praised for its ability to rally large numbers of people around social or political causes, but in this case, Brady said the "mob mentality" took over and made him feel unwelcome. He ultimately left the site."Kyle had a bad experience, and I think we were able to learn from that experience, and the community has been better for it," McComas said.

"Getting paper clips" has since become something of a meme for RedditGifts users.